1. Field of the Invention
The present invention relates to a stacked modular jack assembly, and particularly to a stacked LAN (Local Area Network) jack assembly having built-in circuit boards each having signal conditioning components thereon for ensuring high signal transmission performance of the jack assembly.
2. Description of Related Art
It is quite common to use modular jacks for the data transmission in high speed applications such as IEEE 802.3 10Base-T or 100Base-T local area networks. A common problem to these high speed modular jacks is their tendency to emit high frequency radiation. There is also a need to provide means for suppressing undesirable noise.
Noise suppressors or signal conditioning components, such as common mode choke coils, are known in the art. The noise suppressors are mounted on a mother board on which the modular jack is seated. The noise suppressors are electrically connected with the modular jack by traces on the mother board. However, such signal conditioning components consume board real estate, which could otherwise be used for other circuitry. Furthermore, since the signal conditioning components are distant from the modular jack, the signal traces required to route the signals from the modular jack to the signal conditioning components degrade the signal integrity somewhat, thereby lowering the signal-to-noise ratio.
Stewart, headquartered in Glen Rock, Pa., posted an article, entitled xe2x80x9cMagJack Family of Modular Jacks with Integrated Magneticsxe2x80x9d on the Internet website address, http://www.stewartconnector.com/pdfs/magjkfypdf. This article introduces a series of magjack modular connectors each having integrated magnetic components housed within a jack body for protecting signals from internally and externally generated noise. Because the magnetic components are integrated into the jack itself, valuable board real estate is obviously saved.
U.S. Pat. No. 5,069,641, assigned to Murata Manufacturing Co., Ltd., discloses a modular jack assembly comprising a dielectric housing and a printed circuit board disposed within the housing. The printed circuit board contains noise suppressors. A common mode choke coil and a three-terminal capacitor arrangement is used as a typical of the noise suppressor. The printed circuit board is fitted with contactors and terminals respectively for contacting with a modular plug and for mounting the modular jack assembly on a mother board. The contactors and the terminals are electrically connected with the noise suppressors by traces on the printed circuit board.
U.S. Pat. Nos. 5,587,884 and 5,647,767, both assigned to The Whitaker Corporation, each disclose a modular jack assembly comprising an insulating housing and an insert subassembly received in the housing. The insert subassembly includes front and rear insert members. The front insert member has contact terminals encapsulated therein for mating with a modular plug. The rear insert member has a printed circuit board and leads encapsulated therein. The printed circuit board contains signal conditioning components such as common mode choke coils. The leads extend downwardly for electrically connecting to external circuits, such as a mother board. The terminals and the leads are soldered to the printed circuit board and electrically connected with the signal conditioning components by traces on the printed circuit board.
U.S. Pat. No. 5,687,233, assigned to Maxconn Incorporated, discloses a modular jack assembly addressing the problem encountered in the ""884 and ""767 patents. The modular jack assembly employs a various of signal conditioning components such as capacitors and magnetic coils to provide sufficient conditioning of data transmission. Signal pins are divided into a contact pin array and a mounting pin array. The two pin arrays are electrically coupled through an internal printed circuit board (PCB) which carries the capacitors and magnetic coils. However, because the capacitors and magnetic coils are all mounted on the same printed circuit board, mutual interference between the signal conditioning components may also be a problem.
Recently, in order to save valuable real estate of mother boards in electronic devices, modular jacks are developed to be arranged in a stacked manner. When the stacked jack is used in high speed applications and required to have better signal transmission performance, a number of signal conditioning components will be mounted onto a PCB which is received in the stacked jack. The PCB is an expensive multi-layer printed circuit board so that it can have sufficient conductive lines to interconnect the signal conditioning components in a predetermined pattern. In addition, there is no available space on the PCB for more electrical components needed for suppressing crosstalk between adjacent contacts.
Hence, the present invention aims to provide a stacked jack assembly having an additional built-in PCB on which some signal conditioning components are mounted to thereby overcome the disadvantages of the prior art.
Accordingly, a first object of the present invention is to provide a stacked modular jack assembly having built-in circuit boards each with signal conditioning components attached thereon for achieving better signal transmission performance therethrough.
A second object of the present invention is to provide a modular jack assembly having built-in circuit boards each with signal conditioning components attached thereon for conditioning signals, and each circuit board having a simplified circuit design.
In order to achieve the objects set forth, an electrical connector assembly in accordance with the present invention comprises an insulating housing and an electrical subassembly disposed within the housing. The electrical subassembly includes first and second contact array assemblies each having a PCB and a plurality of contacts soldered on the PCB, a pair of magnetic modules respectively connected with the first and second PCBs, and a third PCB containing signal conditioning components. Each magnetic module has upper pins, lower pins for soldering to a mother board and magnetic coils connecting between the upper and lower pins via some of the upper pins thereof. The others of the upper pins of the magnetic modules are electrically connected to the signal conditioning components on the third PCB.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.